Add some tests for RelocVisitor.

Patch by Charlie Turner.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219107 91177308-0d34-0410-b5e6-96231b3b80d8
Refactor RelocVisitor to take an object. This removes some
string comparisons and makes it a bit easier to check individual
targets.

Patch by Charlie Turner.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219108 91177308-0d34-0410-b5e6-96231b3b80d8
Add support for ARM and AArch64 big endian objects to
RelocVisitor.

Patch by Charlie Turner.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219109 91177308-0d34-0410-b5e6-96231b3b80d8
For biendian targets like ARM and AArch64, it is useful to have the
output of the llvm-dwarfdump and llvm-objdump report the endianness
used when the object files were generated.

Patch by Charlie Turner.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219110 91177308-0d34-0410-b5e6-96231b3b80d8